Three columns of volcanic rock shoot out of the ocean.

If a glacial river suddenly diving into a sheer chasm via a dramatic, multi-stage waterfall isn't peak Iceland, it's certainly close.

One of the tallest buildings in Iceland, and perhaps, the most visually impressive.

This valley of hot springs and boiling mud pots is home to the record-holding "Geysir," which originated the English word.

This bridge was constructed from the rubble of the infamous Bastille.

This life-size replica of the Statue of Liberty's flame is also a tribute to Princess Diana by default.

This former “ante-chamber to the guillotine” has been refurbished to illustrate the brutal history of French justice.

A favorite Paris bar for U.S. expats, including Gershwin, Hemingway, and James Bond.

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

This modest marker near Notre Dame identifies the very center of Paris.

Site of a classic 19th-century physics experiment to prove the earth is rotating.

An "inside out" building in the historical center of Paris, featuring Europe’s largest modern art museum.

This large midwestern cavern features impressive rock formations and an underground waterfall.

A whimsical sensor instrument for Minneapolitans to play on their walks to work.

On a former island, this old fortification once used to protect the Boston Area and started Edgar Allan Poe in his military career.

Civil War-era Fort designed to withstand invasion and attack, with tricky traps called "murder holes."

Civil War Fort on an island in the Boston Harbor.

Go surfing on this urban wave, "hacked" by local surfers.

What happens when a sculptor has to find a way around a 100-year-old copyright.

Macabre headstones carved with winged skulls, dancing skeletons, and pithy reminders of impending death.

The site of Paul Revere's historic two lantern warning.

The composer did some of his finest work in this country home, including "The Nutcracker."

The summit Roosevelt conquered before he descended to become The Chief.